Most deployable solar arrays for spacecraft have used crystalline solar cells mounted to rigid honeycomb panels. Certain prior art describes mechanisms to effectively package, carefully deploy, and maintain the shape of arrays of rigid panels. Flexible solar arrays have also been used, but have been limited to crystalline solar cell arrays packaged in a long roll or pleated stack that is deployed using a separate boom or booms.
Spacecraft most commonly use solar cells to collect solar radiation and convert it into the electrical power necessary to operate the spacecraft. The solar cells are normally disposed on a solar array. A solar array typically comprises one or more solar panels electrically attached to each other and to the spacecraft. Each solar panel in an array typically comprises numerous individual solar cells, which are usually laid out in rows and connected together electrically at their adjacent edges. These photovoltaic cells form a two-dimensional array and are frequently mounted on a rigid honeycomb composite solar panel.
Optimization of standard solar array systems (complete/assembled structural and electrical wing system) incorporating standard thickness multijunction solar cells (nominally 140 um thick cells with 100 um thick coverglass) are approaching ˜100 W/kg BOL specific power and ˜13 kW/m3 stowed packaging performance plateaus. Current state-of-the-art optimized solar array systems utilize heavy carbon composite honeycomb panel-structures to provide necessary deployed/stowed strength and stiffness (frequency) to meet mission requirements. Additionally, these current rigid honeycomb panel solar arrays require very complex and complicated synchronization mechanisms to ensure reliable and repeatable deployment control. Other promising solar array arrays that incorporate flexible blanket technologies promise even higher specific power beyond 100 W/kg and more compact stowed packaging performance, but because these structures must also support and protect the standard-thickness heavy multijunction solar cells their performance metrics are also reaching a plateau. These lighter weight flexible blanket solar arrays always require complex mechanisms to ensure reliable and repeatable deployment control. State-of-the-art deployable solar array structures also occupy large stowage volumes. In some cases the large stowage envelopes are beginning to interfere within the allocated launch volumes and are prohibiting the ability to provide significant power growth for future missions (i.e., more power requires more volume, which is not available).
The new proposed solar array embodiment, an elastically deployable panel structure, has been created to significantly simplify the complex mechanisms required for deployment control, and to significantly simplify the overall structure composition to provide high specific power, low/mid power capability, high reliability, compact stowed volume, high structural performance (stiffness), modularity, reconfigurability, simplicity/reduction in piece part components, and affordability.
The primary prior art solar arrays in the subject field are comprised of rigid honeycomb panel structures interconnected with discrete hingelines and deployment mechanization. These solar array types are not elastically deployable structures that deploy from their own strain energy, but are prior art in terms of solar array systems in the relevant field.
Flexible photovoltaic arrays have also been implemented in the subject field. The most notable and technically mature flexible blanket solar arrays produced to date, and an indication of their blanket construction, are listed below:                ATK's UltraFlex which is a radial rib structure with tensioned single layer open weave mesh substrate blanket (open backside)—motor driven deployment        Lockheed Martin's SAFE (Solar Array Flight Experiment), International Space Station (ISS), and Milstar all of which are a central structure tensioned rectangular Kapton glass-reinforced blanket—motor driven deployment        ESA/British Aerospace Hubble Space Telescope (HST) which is a dual-side structure tensioned rectangular Kapton glass-reinforced blanket—motor driven deployment        AEG-Telefunken/Spar Aerospace L-SAT and Olympus which is a central structure with tensioned rectangular Kapton glass-reinforced blanket—motor driven deployment        Northrop Grumman (TRW) EOS-AM/Terra and APSA which is a central structure with tensioned rectangular Kapton carbon-reinforced blanket—motor driven deployment        Boeing (Hughes) FRUSA which is a dual-sided structure tensioned rectangular Kapton glass-reinforced blanket, and flown in 1971—motor driven deployment        DSS ROSA—Roll-Out-Solar-Array which is a dual side structure tensioned rectangular dimensionally stable blanket—elastically deployable or motor driven deployment.        
With the exception of DSS's ROSA solar array, all past solar array flexible blanket solar arrays developed, built, and flown to date are deployed through electrical motor actuation. As such, these past solar arrays are not elastically deployable structures, except the DSS ROSA system. DSS's innovative Roll-Out Solar Array (ROSA) relies on a highly reliable innovative self-elastically deployable Roll-Out Boom that deploys immediately and predictably under its own strain energy. One other notable solar system that is in development that also does not deploy with a motor is from Composite Technology Development (CTD). CTD's non-motor driven solar array integrates unique elastic memory composite materials (EMC—also referred to as shape memory composites—SMC) that deploys from a stowed state to a deployed state through the application of heat.
The proposed elastically deployable panel structure for solar array applications that is described herein is uniquely different from all solar array structures to date, and as previously referenced. The panel solar array structure does not consist of separate boom(s) used to deploy a separate flexible solar array blanket, but rather the entire assembly is a unified panel structure that uniquely serves a dual use purpose as the structural platform and the carrier for the photovoltaic modules. Photovoltaic modules may be mounted to the panel structure itself or to windows within the panel structure. The elastically deployable panel structure may be rolled or folded to a compact stowage volume and forms a stiff, stable, structure when deployed. Implementation of an elastically deployable panel structure minimizes the required deployment mechanization, reduces parts count, increases the system reliability and reduces the system cost. The proposed embodiment targets small to mid-power-level solar array applications and eliminates the deficiencies of current state-of-the-art solar array structure technologies.